Substrate processing apparatus and method of manufacturing semiconductor device

ABSTRACT

There is provided a substrate processing apparatus including a process chamber defined at least by a reaction tube and a furnace opening part provided at a lower portion of the reaction tube; a nozzle provided at the furnace opening part and extending from the furnace opening part to an inside of the reaction tube; a gas supply system provided at an upstream side of the nozzle; a blocking part provided at a boundary between the gas supply system and the nozzle; and a controller configured to control the gas supply system and the blocking part such that the blocking part co-operates with the gas supply system to supply gases into the process chamber through the nozzle.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This non-provisional U.S. patent application claims priority under 35U.S.C. § 119 of International Application No. PCT/JP2016/066915, filedon Jun. 7, 2016, in the WIPO, the entire contents of which are herebyincorporated by reference.

BACKGROUND 1. Field

The present disclosure relates to a substrate processing apparatus and amethod of manufacturing a semiconductor device.

2. Description of the Related Art

A semiconductor manufacturing apparatus is an example of a substrateprocessing apparatus. As the semiconductor manufacturing apparatus, forexample, a vertical type apparatus (also referred to as a “vertical typesemiconductor manufacturing apparatus”) may be used. Recently, in orderto form various films, the semiconductor manufacturing apparatus of thevertical type may include a plurality of opening/closing valves and agas supply system including two or more gas supply mechanisms. Ingeneral, as shown in FIG. 4, the semiconductor manufacturing apparatusincludes a piping including a flexible pipe. The flexible pipe is usedfor the piping provided from a furnace opening part to anopening/closing valve closest thereto. Although the length of theflexible pipe varies depending on the layout of the substrate processingapparatus, the length of the flexible pipe was about 500 mm to 3,000 mm.

Particles originated from by-products adhered to such piping includingthe flexible pipe provided from the furnace opening part to theopening/closing valve closest thereto may be discharged into a reactiontube of the substrate processing apparatus. When the dischargedparticles adhere to a substrate, the characteristics of a semiconductordevice may be affected. Therefore, in order to prevent theabove-described problem, while supplying a film-forming gas into thepiping, N₂ gas is simultaneously supplied into another piping where thefilm-forming gas is not supplied. However, by supplying the N₂ gas(hereinafter, also referred to as “counter N₂ gas”), the concentrationof the film-forming gas becomes non-uniform in the reaction tube.Therefore, the uniformity of film thickness may deteriorate in asubstrate processing.

As a configuration for eliminating the need for the counter N₂ gas, anopening/closing valve may be installed at a pipe of the gas supplysystem close to a process furnace of the substrate processing apparatus.However, it is difficult to install the opening/closing valve at thepipe of the gas supply system close to the process furnace for thereasons such as the restriction of the space for installing the valveand the limit of the heat resistant temperature of the valve. Accordingto some related arts, a valve may be installed at a pipe close to thefurnace opening part. However, a configuration for eliminating the needfor the counter N₂ gas is not disclosed in the related arts.

SUMMARY

Described herein is a technique capable of providing an opening/closingvalve in the vicinity of a furnace opening part.

According to one aspect of the technique described herein, there isprovided a substrate processing apparatus including:

a process chamber defined at least by a reaction tube and a furnaceopening part provided at a lower portion of the reaction tube;

a nozzle provided at the furnace opening part and extending from thefurnace opening part to an inside of the reaction tube;

a gas supply system provided at an upstream side of the nozzle;

a blocking part provided at a boundary between the gas supply system andthe nozzle; and

a controller configured to control the gas supply system and theblocking part such that the blocking part co-operates with the gassupply system to supply gases into the process chamber through thenozzle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates a vertical cross-section of a processfurnace of a substrate processing apparatus preferably used in one ormore embodiments described herein.

FIG. 2 schematically illustrates a horizontal cross-section of areaction tube of the substrate processing apparatus preferably used inthe embodiments.

FIG. 3 is a block diagram schematically illustrating a configuration ofa controller and components controlled by the controller of thesubstrate processing apparatus preferably used in the embodiments.

FIG. 4 schematically illustrates a piping structure in the vicinity of aconventional furnace opening part.

FIG. 5 schematically illustrates an exemplary configuration of blockingparts, gas supply pipes and nozzles preferably used in the embodiments.

FIG. 6 schematically illustrates another exemplary configuration ofblocking parts, gas supply pipes and nozzles preferably used in theembodiments.

FIG. 7 schematically illustrates an exemplary configuration of a furnaceopening part preferably used in the embodiments.

FIG. 8 schematically illustrates another exemplary configuration of thefurnace opening part of the substrate processing apparatus preferablyused in the embodiments.

FIG. 9 schematically illustrates an exemplary configuration of a shutoff valve e preferably used in the embodiments.

FIG. 10 schematically illustrates another exemplary configuration of theshut off valve preferably used in the embodiments.

FIG. 11 is a diagram showing an exemplary flow of a substrate processingfor supplying process gases by operating the shut off valve preferablyused in the embodiments.

FIG. 12 is a diagram showing results of the substrate processingobtained by supplying the process gases by operating the shut off valvepreferably used in the embodiments.

FIG. 13 is a diagram showing a comparison result between the substrateprocessing with and without the shut off valve using a film-formingsequence preferably used in the embodiments.

DETAILED DESCRIPTION Embodiments

A substrate processing apparatus according to one or more embodiments ofthe technique is configured as an example of a semiconductormanufacturing apparatus used for manufacturing a semiconductor device.Specifically, the substrate processing apparatus includes a processchamber defined at least by a reaction tube and a furnace opening partprovided at a lower portion of the reaction tube; a nozzle provided atthe furnace opening part and extending from the furnace opening part toan inside of the reaction tube; a process gas supply system provided atan upstream side of the nozzle; a blocking part provided at a boundarybetween the process gas supply system and the nozzle; and a controllerconfigured to control the process gas supply system and the blockingpart such that the blocking part co-operates with the process gas supplysystem to supply gases into the process chamber through the nozzle.

The blocking part connected to the nozzle extending from an inner wallof the furnace opening part to the inside of the reaction tube isprovided at the furnace opening part without providing a pipe betweenthe blocking part and an outer wall of the furnace opening part. In thisconfiguration, the blocking part is installed almost directly under aprocess furnace (in the vicinity of the furnace opening part). Thus, itis preferable to provide a cooling mechanism so that the shut off valve(blocking part) can be cooled. In addition, as a countermeasure againstthe heat buildup in the furnace opening part, it is preferable toprovide a furnace opening exhaust mechanism capable of performing localexhaust of the furnace opening part. The cooling mechanism may be alsoreferred to as a “cooling part”. The cooling mechanism and the furnaceopening exhaust mechanism will be described later.

In the embodiments, a structure in which the furnace opening part andthe shut off valve are integrated as a united body (for example, nopiping including a flexible pipe is provided between the furnace openingpart and the shut off valve) may also be simply referred to as a“furnace opening part”.

Hereinafter, the embodiments according to the technique will bedescribed with reference to figures such as FIG. 1 and FIG. 2. First, asshown in FIG. 1, a process furnace 202 includes a heater 207 serving asa heating apparatus (heating mechanism). The heater 207 is cylindrical,and includes a heater wire (not shown) and a heat insulating material(not shown). A lower portion of the heater 207 is supported by a heaterbase (not shown) serving as a support plate, so that the heater 207 isinstalled in a vertical orientation. In addition, the heater 207 alsofunctions as an activation mechanism (excitation mechanism) foractivating (exciting) process gases by heat.

A reaction tube 203 having a single tube structure and constituting areaction vessel (process vessel) is provided in the heater 207 so as tobe concentric with the heater 207. The reaction tube 203 is made of aheat-resistant material such as quartz (SiO₂) and silicon carbide (SiC).A lower end of the reaction tube 203 is open, and an upper end of thereaction tube 203 is constituted by a ceiling closed by a flat wall. Theupper end of the reaction tube 203 (hereinafter, also referred to as a“ceiling portion”) is formed thick to secure the strength of thereaction tube 203. A side wall of the reaction tube 203 is constitutedby a cylindrical portion formed in a cylindrical shape, and a gas supplyregion 222 and a gas exhaust region 224 are provided on an outer wall ofthe cylindrical portion. A process chamber 201 is provided in thereaction tube 203 including the gas supply region 222 and the gasexhaust region 224. The process chamber 201 is defined by the reactiontube 203 and a furnace opening part which will be described later. Theprocess chamber 201 is configured such that wafers 200 serving assubstrates are processed therein, and accommodates a boat 217 capable ofsupporting vertically arranged wafers 200 in a horizontal orientation ina multistage manner. The heater 207 is provided so as to surround thereaction tube 203. The heater 207 can heat the wafers 200 accommodatedin the boat 217 in the reaction tube 203 (or in the process chamber 201)to a predetermined temperature. The boat 217 serves as a substrateretainer.

The gas supply region 222 is constituted by a protruding portionprotruding outward from a sidewall of the cylindrical portion of thereaction tube 203. An outer wall of the gas supply region 222 is locatedouter than a part of the cylindrical portion of the reaction tube 203,and is concentrical with the cylindrical portion with a diameter largerthan an outer diameter of the cylindrical portion. A lower end of thegas supply region 222 is open, and an upper end of the gas supply region222 is constituted by a ceiling closed by a flat wall. Nozzle parts 340a, 340 b and 340 c which will be described later are accommodated in thegas supply region 222 along the longitudinal direction (that is,vertical direction). Gas supply slits 235 are provided at a partitionwall 254 which is arranged along a boundary between the gas supplyregion 222 and the cylindrical portion. The partition wall 254 may bereferred to a side wall of the cylindrical portion. An outer sidesurface of the partition wall 254 constitutes a side portion facing thegas supply region 222. Hereinafter, for example, the nozzle parts 340 athrough 340 c may be collectively referred to as a nozzle part 340. Thesame also applies to other components described herein such as ablocking part 101. That is, blocking parts 101 a, 101 b and 101 c may becollectively referred to as the blocking part 101.

The gas exhaust region 224 is constituted by a protruding portionprotruding outward from a sidewall of the cylindrical portion at aregion other than where the gas supply region 222 is provided. Thewafers 200 of the process chamber 201 are accommodated in a regionbetween the gas supply region 222 and the gas exhaust region 224. Anouter wall of the gas exhaust region 224 is provided concentrically withthe cylindrical portion, and is located outer than the cylindricalportion with a diameter larger than the outer diameter of thecylindrical portion. A lower end of the gas exhaust region 224 and anupper end of the gas exhaust region 224 are constituted by ceilingsclosed by flat walls. Gas exhaust slits 236 are provided at a partitionwall 252 arranged along a boundary between the gas exhaust region 224and the cylindrical portion. The partition wall 252 may be referred to aside wall of the cylindrical portion. An outer side surface of thepartition wall 252 constitutes a side portion facing the gas exhaustregion 224.

The lower end of the reaction tube 203 is supported by a cylindricalmanifold 226 serving as the furnace opening part. The manifold 209 ismade of a metal such as a nickel alloy and stainless steel (SUS), or ismade of a heat resistant material such as quartz (SiO₂) and siliconcarbide (SiC). A flange (not shown) is provided at an upper end of themanifold 226. The lower end of the reaction tube 203 is provided on theflange and supported by the flange. A sealing member 220 such as anO-ring is provided between the flange and the lower end of the reactiontube 203 to airtightly seal the inside of the reaction tube 203.

A seal cap 219 is airtightly attached to a lower end opening of themanifold 226 via a sealing member 220 such as an O-ring. The seal cap219 is configured to airtightly seal a lower end opening of the reactiontube 203, that is, the lower end opening of the manifold 226. Forexample, the seal cap 219 is made of a metal such as a nickel alloy orstainless steel, and is disc-shaped.

A boat support 218 configured to support the boat 217 is provided on theseal cap 219. The boat support 218 is made of a heat-resistant materialsuch as quartz and silicon carbide. The boat support 218 functions as aheat insulating part. The boat support 218 also serves as a support bodyfor supporting the boat 217. The boat 217 includes a bottom plate (notshown) fixed to the boat support 218 and a top plate (not shown)provided above the bottom plate. A plurality of support columns (notshown) are provided between the bottom plate and the top plate. Forexample, the boat 217 is made of a heat resistant material such asquartz or silicon carbide.

A boat rotating mechanism 267 to rotate the boat 217 is provided underthe seal cap 219 opposite to the process chamber 201. A rotating shaft(not shown) of the boat rotating mechanism 267 is connected to the boat217 through the seal cap 219. As the boat rotating mechanism 267 rotatesthe boat 217 via the boat support 218, the wafers 200 supported by theboat 217 are rotated. The seal cap 219 may be moved upward/downward inthe vertical direction by a boat elevator 115 provided outside thereaction tube 203. The boat elevator 115 serves as an elevatingmechanism. As the seal cap 219 is moved upward/downward by the boatelevator 115, the boat 217 is loaded into the process chamber 201 orunloaded out of the process chamber 201.

A nozzle support part 350 for supporting the nozzle part 340 is providedin the manifold 226. The nozzle support part 350 is L-shaped andprovided through a side wall of the manifold 226. In the embodiments,for example, three nozzle support parts 350 a, 350 b and 350 c servingas the nozzle support part 350 are provided. The nozzle support part 350is made of a material such as a nickel alloy and stainless steel. A gassupply pipe 310 for supplying a gas into the reaction tube 203 isconnected to an end of the nozzle support part 350 on the side of thereaction tube 203 via the blocking part 101 serving as a shut off valve.In the embodiments, the blocking part 101 may also be referred to as ashut off valve 101.

The nozzle parts 340 a, 340 b and 340 c are connected to the other endsof the nozzle support parts 350 a, 350 b and 350 c, respectively. Forexample, the nozzle part 340 is made of a heat resistant material suchas quartz and SiC. A nozzle is constituted by the nozzle support part350 and the nozzle part 340. A shut off valve 101 provided at theboundary between the nozzle and the gas supply pipe 310 is fixed in thevicinity of the manifold 226. In addition, the nozzle may be configuredsuch that the nozzle support part 350 and the nozzle part 340 areintegrated.

The nozzle part 340 is provided in the gas supply region 222. The nozzlepart 340 extends from a lower portion to an upper portion of the gassupply region 222 along the longitudinal direction of the gas supplyregion 222 (that is, vertical direction). For example, the nozzle parts340 a and 340 c are I-shaped long nozzle, respectively. A plurality ofgas supply holes 234 a and a plurality of gas supply holes 234 c forsupplying gases are provided at side surfaces of the nozzle parts 340 aand 340 c, respectively. The plurality of gas supply holes 234 a and theplurality of gas supply holes 234 c are open toward the center of thereaction tube 203. For example, the nozzle part 340 b is I-shaped shortpipe nozzle (that is, I-shaped short nozzle). The nozzle part 340 b isprovided with an opening portion 234 b, and a front end of the nozzlepart 340 b is open. As described above, for example, three nozzleportions 340 a through 340 c are provided in the gas supply region 222and are configured to supply various types of gases into the processchamber 201. The nozzle part 340 may be, for example, I-shaped orL-shaped, but the shape of the nozzle part 340 is not limited thereto.

The boat 217 accommodating the wafers 200 to be batch-processed isloaded into the process chamber 201 of the above-described processfurnace 202 while being supported by the boat support 218. The wafers200 are accommodated in the boat 217 in a multistage manner. The heater207 is configured to heat the wafers 200 loaded in the process chamber201 to a predetermined temperature.

A first gas supply source (not shown) for supplying a first process gas(also referred to as a “first gas”), a mass flow controller (MFC) 320 aserving as a flow rate controller (flow rate control mechanism) and avalve 330 a serving as an opening/closing valve are sequentiallyprovided at a gas supply pipe 310 a from the upstream side toward thedownstream side of the gas supply pipe 310 a. A shut off valve 101 a isprovided at a boundary between the gas supply pipe 310 a and the nozzlesupport part 350 a. The shut off valve 101 a is installed in thevicinity of the outside of the manifold 226. For example, the manifold226 and the shut off valve 101 a are integrally provided withoutproviding a flexible pipe between the manifold 226 and the shut offvalve 101 a. In addition, an exhaust part 102 a which will be describedlater may be provided so as to be adjacent to the shut off valve 101 a.

A second gas supply source (not shown) for supplying a second processgas (also referred to as a “second gas”), a mass flow controller (MFC)320 b serving as a flow rate controller (flow rate control mechanism)and a valve 330 b serving as an opening/closing valve are sequentiallyprovided at a gas supply pipe 310 b from the upstream side toward thedownstream side of the gas supply pipe 310 b. A shut off valve 101 b isprovided at a boundary between the gas supply pipe 310 b and the nozzlesupport part 350 b. The shut off valve 101 b is installed in thevicinity of the outside of the manifold 226. For example, the manifold226 and the shut off valve 101 b are integrally provided withoutproviding a flexible pipe between the manifold 226 and the shut offvalve 101 b. In addition, an exhaust part 102 b which will be describedlater may be provided so as to be adjacent to the shut off valve 101 b.

A third gas supply source (not shown) for supplying a third process gas(also referred to as a “third gas”), a mass flow controller (MFC) 320 cserving as a flow rate controller (flow rate control mechanism) and avalve 330 c serving as an opening/closing valve are sequentiallyprovided at a gas supply pipe 310 c from the upstream side toward thedownstream side of the gas supply pipe 310 c. A shut off valve 101 c isprovided at a boundary between the gas supply pipe 310 c and the nozzlesupport part 350 c. The shut off valve 101 c is installed in thevicinity of the outside of the manifold 226. For example, the manifold226 and the shut off valve 101 c are integrally provided withoutproviding a flexible pipe between the manifold 226 and the shut offvalve 101 c. In addition, an exhaust part 102 c which will be describedlater may be provided so as to be adjacent to the shut off valve 101 c.

Gas supply pipes 310 d, 310 e and 310 f are connected to the downstreamsides of the valves 330 a, 330 b and 330 c provided at the gas supplypipes 310 a, 310 b and 310 c, respectively. Mass flow controllers (MFCs)320 d, 320 e and 320 f serving as flow rate controllers (flow ratecontrol mechanisms) and valves 330 d, 330 e and 330 f serving asopening/closing valves are sequentially provided at the gas supply pipes310 d, 310 e and 310 f from the upstream sides toward the downstreamsides of the gas supply pipes 310 d, 310 e and 310 f, respectively.

A first process gas supply system is constituted mainly by the gassupply pipe 310 a, the MFC 320 a and the valve 330 a. In the presentspecification, the first process gas supply system may be also referredto as a first process gas supply mechanism. The first process gas supplysystem may further include the first gas supply source, the nozzlesupport part 350 a, the nozzle part 340 a and the shut off valve 101 a.The first process gas supply system may be constituted by a first pipingpart including the gas supply pipe 310 a, the MFC 320 a and the valve330 a; a first boundary part including at least the first blocking part101 a; and a first nozzle constituted by at least the nozzle supportpart 350 a and the nozzle part 340 a. For example, according to theembodiments, the first process gas serving as a reactive gas is suppliedthrough the first process gas supply system.

A second process gas supply system is constituted mainly by the gassupply pipe 310 b, the MFC 320 b and the valve 330 b. In the presentspecification, the second process gas supply system may be also referredto as a second process gas supply mechanism. The second process gassupply system may further include the second gas supply source, thenozzle support part 350 b, the nozzle part 340 b and the shut off valve101 b. The second process gas supply system may be constituted by asecond piping part including the gas supply pipe 310 b, the MFC 32 b andthe valve 330 b; a second boundary part including at least the secondblocking part 101 b; and a second nozzle constituted by at least thenozzle support part 350 b and the nozzle part 340 b. For example,according to the embodiments, the second process gas serving as a sourcegas is supplied through the second process gas supply system.

A third process gas supply system is constituted mainly by the gassupply pipe 310 c, the MFC 320 c and the valve 330 c. In the presentspecification, the third process gas supply system may be also referredto as a third process gas supply mechanism. The third process gas supplysystem may further include the third gas supply source, the nozzlesupport part 350 c, the nozzle part 340 c and the shut off valve 101 c.The third process gas supply system may be constituted by a third pipingpart including the gas supply pipe 310 c, the MFC 320 c and the valve330 c; a third boundary part including at least the third blocking part101 c; and a third nozzle constituted by at least the nozzle supportpart 350 c and the nozzle part 340 c. For example, according to theembodiments, the third process gas is supplied through the third processgas supply system. The third process gas serves as a reactive gas or aninert gas that does not contribute to a substrate processing. Theconfigurations of the process gas supply systems and the shut off valve101 will be described later.

In the present specification, the term “process gas” may indicate onlythe first process gas, indicate only the second process gas, indicateonly the third process gas, or indicate all of the first process gas,the second process gas and the third process gas. In addition, in thepresent specification, the term “process gas supply system” may indicateonly the first process gas supply system (first process gas supplymechanism), indicate only the second process gas supply system (secondprocess gas supply mechanism), indicate only the third process gassupply system (third process gas supply system), or indicate all of thefirst process gas supply system, the second process gas supply systemand the third process gas supply system. In the present specification,the process gas supply system may be simply referred to as a “gas supplysystem”.

An exhaust port 230 is provided under the gas exhaust region 224. Theexhaust port 230 is connected to an exhaust pipe 232. A vacuum pump 246serving as a vacuum exhauster is connected to the exhaust pipe 232through a pressure sensor 245 and an APC (Automatic Pressure Controller)valve 244. The pressure sensor 245 serves as a pressure detector(pressure detection mechanism) to detect an inner pressure of theprocess chamber 201, and the APC valve 244 serves as an pressurecontroller (pressure adjusting mechanism). The vacuum pump 246 isconfigured to vacuum-exhaust the inside of the process chamber 201 suchthat the inner pressure of the process chamber 201 reaches apredetermined pressure (vacuum degree). The APC valve 244 includes anopening/closing valve. With the vacuum pump 246 in operation, the APCvalve 244 may be opened/closed to vacuum-exhaust the process chamber 201or stop the vacuum exhaust. With the vacuum pump 246 in operation, byadjusting an opening degree of the APC valve 244, the APC valve 244 isconfigured to adjust the inner pressure of the process chamber 201 byadjusting the conductance. An exhaust system is constituted mainly bythe exhaust pipe 232, the APC valve 244 and the pressure sensor 245. Theexhaust system may further include the vacuum pump 246.

By executing a process recipe describe later, a controller 280 whichwill be described later is configured to control: (A) a transfer systemincluding components such as the boat elevator 115 and the boat rotatingmechanism 267; (B) a temperature control system including componentssuch as the heater 207; (C) the process gas supply system includingcomponents such as the MFC 320, the valves 330 and the blocking part101; and (D) a gas exhaust system including components such as the APCvalve 244 and the pressure sensor 245.

As shown in FIG. 2, a temperature sensor 1 (hereinafter, also referredto as a “thermocouple”) serving as a temperature detector is provided atthe outside the reaction tube 203. The power supplied to the heater 207is adjusted based on the temperature detected by the temperature sensor1 such that the inner temperature of the process chamber 201 has adesired temperature distribution.

As shown in FIG. 2, the thermocouple 1 is attached to the outside of thereaction tube 203 via a cover 2 serving as a protective part. Forexample, the cover 2 is made of quartz. According to the embodiments,the thermocouple 1 is attached to the outside of the process chamber 201and provided so as to face the heater 207 serving as a heatingapparatus. For example, the thermocouple 1 is fixed by the reaction tube203 and the cover 2.

In FIG. 2, only one thermocouple 1 is shown. However, a plurality ofthermocouples 1 may be provided. In addition, it is possible to providea buffer part (not shown) between the thermocouple 1 and the reactiontube 203. Further, although the thermocouple 1 shown FIG. 2 is providedon the side wall of the reaction tube 203, the thermocouple 1 may beprovided on the ceiling portion of the reaction tube 203.

FIGS. 5 and 6 are schematic diagrams for describing the process gassupply system according to the embodiments. In FIGS. 5 and 6, only twoof the process gas supply systems (i.e., the first process gas supplysystem and the second process gas supply system) are illustrated inorder to help understanding the relationship among the gas supply pipe310, a boundary part (the shut off valve 101) and the nozzle. Byexecuting the process recipe describe later, the controller 280 whichwill be described later is configured to control: (C) the process gassupply system, the blocking part 101, the exhaust part 102 and theswitching part 103. The components of the process gas supply system suchas the process gas supply sources, the MFC 320 and the valve 330 areprovided on the upstream side of the switching part (switching valve)103. However, the components are omitted in FIGS. 5 and 6 forsimplification. The exhaust part 102 may also be referred to as anexhaust valve 102.

A valve (switching valve) closest to the furnace opening part 226 in agas box is a valve that switches between a gas contributing to thesubstrate processing (such as process gas) and a cleaning gas. Thecomponents of the process gas supply system and a cleaning gas supplysystem (not shown) are provided on the upstream side of the switchingpart (switching valve) 103.

According to the embodiments, the gas supply system includes the gassupply pipe 310. The nozzles extend from the furnace opening part 226 tothe inside of the reaction tube 203, and the boundary part includes atleast the blocking part 101. The switching part (switching valve) 103 isconfigured to switch between the gas contributing to the substrateprocessing (such as the process gas) and the cleaning gas, and isprovided at the gas supply pipe 310. The boundary part is connected tothe gas supply pipe 310. It is preferable to provide the exhaust part102 for exhausting a piping including the gas supply pipe 310 betweenthe switching part 103 and the blocking part 101.

Preferably, the substrate processing apparatus may include: the nozzles(the first nozzle and the second nozzle) extending from the furnaceopening part 226 to the inside of the reaction tube 203; the firstprocess gas supply system including at least the gas supply pipe 310 aprovided at the upstream side of the nozzle (the first nozzle); a secondprocess gas supply system including at least the gas supply pipe 310 bprovided at the upstream side of the nozzle (the second nozzle); thefirst blocking part 101 a provided at a boundary between the firstnozzle and the first process gas supply system; and the second blockingpart 101 b provided at a boundary between the second nozzle and thesecond process gas supply system. The reactive gas serving as the firstprocess gas is supplied into the reaction tube 203 by controlling thefirst blocking part 101 a to co-operate with the first process gassupply system, and the source gas serving as the second process gas issupplied into the reaction tube 203 by controlling the second blockingpart 101 b to co-operate with the second process gas supply system. Theabove-described components such as the first process gas supply system,the first blocking part 101 a, the second process gas supply system andthe second blocking part 101 b are controlled by the controller 280shown in FIGS. 5 and 6.

As described above, the boundary part including the shut off valve(blocking part) 101 is provided. By opening the shut off valve 101 a andclosing the shut off valve 101 b, the gas supply pipe 310 b and theinside of the reaction tube 203 can be blocked when the first processgas is supplied through the gas supply pipe 310 a and the first nozzle.Thus, it is possible to suppress the back diffusion of the first processgas into the gas supply pipe 310 b. In addition, by opening the shut offvalve 101 b and closing the shut off valve 101 a, the gas supply pipe310 a and the inside of the reaction tube 203 can be blocked when thesecond process gas is supplied through the gas supply pipe 310 b and thesecond nozzle. Thus, it is possible to suppress the back diffusion ofthe second process gas into the gas supply pipe 310 a.

Particularly, in the case of using the source gas as the second processgas according to the embodiments, the shut off valve 101 a is closedwhile the shut off valve 101 b is opened to supply the source gas intothe reaction tube 203 through the second nozzle. By closing the shut offvalve 101 a, the gas supply pipe 310 a and the inside of the reactiontube 203 are blocked. Thus, it is possible to completely suppress theback diffusion of the source gas into the gas supply pipe 310 a. As aresult, it is possible to reduce particles originated from by-productsgenerated in the gas supply pipe 310.

As shown in FIG. 5 by a dot-and-dash line, a furnace opening box capableof performing local exhaust of the furnace opening part 226 may beprovided so as to surround the furnace opening part 226. The furnaceopening box can be used for preventing the gas leaks and the heatbuildup in the furnace opening part 226. An inner atmosphere of thefurnace opening box is a high temperature atmosphere of 50° C. to 200°C. In general, the heat resistant temperature of a valve is about 150°C. Thus, it is possible to use a heat resistant valve having a heatresistant temperature from 250° C. to 300° C. in the embodiments.However, even when the heat resistant valve is used, the operatinglifetime of the heat resistant valve may be remarkably lowered and thereplacement frequency may be shortened if the inner atmosphere of thefurnace opening box is the high temperature atmosphere. As acountermeasure against the above-described problem, it is possible toadd a cooling mechanism to the blocking part 101. Therefore, it ispossible to provide a valve in the furnace opening box even when theinner temperature of the furnace opening box exceeds the heat resistanttemperature of the valve.

As shown in FIG. 9, a heat radiation method using coolant (coolingwater) may be used as a cooling method. For example, a cooling blockcovers the shut off valve 101. As long as the inner temperature of thefurnace opening box can be kept below the heat resistant temperature ofthe valve, it does not matter what kind of cooling method is used. Forexample, the cooling part may be configured to supply the coolant to theblocking part 101.

The exhaust system for exhausting the gas in the reaction tube 203 isprovided. The controller 280 is configured to close the first blockingpart and the second blocking part and to control the exhaust system toexhaust the unreacted source gas or the unreacted reactive gas from thereaction tube 203 when the supply of the reactive gas or the source gasto the substrates in the reaction tube 203 is completed. In addition,the controller 280 is configured to control the first process gas supplysystem, the first blocking part, the second process gas supply system,the second blocking part and the exhaust system such that the inside ofthe process chamber 201 is purged cyclically by adjusting the flow rateof the inert gas supplied into the reaction tube 203 while the firstblocking part and the second blocking part are opened.

As shown in FIG. 5, the gas supply pipe 310 provided between theswitching part 103 and the boundary part includes a flexible pipe whoseshape is bendable. In the embodiments, the flexible pipe is provided inthe gas supply pipe 310, and may be, for example, bellows-shaped. Theblocking part 101 is installed integrally (or directly) on the side wallof the furnace opening part 226.

As shown in FIG. 5, the flexible pipe is provided in the furnace openingbox. However, the flexible pipe is not limited thereto. For example, theflexible pipe may be provided in a piping between the gas box whereatthe switching part 103 is provided and the furnace opening box whereatthe blocking part 101 is provided. Since the piping between the gas boxand the furnace opening box is installed on site (for example, at asemiconductor manufacturing factory), the installation of the piping isgreatly influenced by conditions such as the layout of the apparatus tobe connected, the facilities in the semiconductor manufacturing factoryand the installation environment of the apparatus. Thus, it is necessaryto adjust the layout or geometrical relationships between individualpipes which may be made of, for example, metal. However, it isimpossible to adjust the layout of the piping when all of the pipes aremade of metal. Therefore, the flexible pipe whose shape is bendable isindispensable.

Conventionally, as shown in FIG. 4, a piping provided between thefurnace opening part 226 and a switching part includes a flexible pipe.However, according to the configuration as shown in FIG. 5, no flexiblepipe is provided between the furnace opening part 226 and the blockingpart 101. In addition, according to the configuration as shown in FIG.6, the gas supply pipe 310 is provided on the upstream side of theblocking part 101, but the flexible pipe provided in the gas supply pipe310 is omitted.

FIG. 6 schematically illustrates a configuration that the exhaust part102 is further provided so as to be adjacent to the blocking part 101 ofthe gas supply system shown in FIG. 5. Since the configuration excludingthe exhaust part 102 is the same as the configuration shown in FIG. 5,only the exhaust part 102 will be described in detail. As shown in FIG.6, the supply piping at the upstream side of the blocking part 101 isbranched off at the exhaust part 102. A vent pipe is connected to theexhaust pipe 232 by the exhaust part 102. With such a configuration, theinside of the gas supply pipe 310 including the flexible pipe betweenthe switching part 103 and the blocking part 101 can be purgedcyclically without purging the reaction tube 203.

For example, in a film-forming sequence described later, the gas supplypipe 310 a can be purged cyclically while supplying the source gas intothe reaction tube 203 through the gas supply pipe 310 b. Therefore, itis possible to improve the degree of cleanliness inside the gas supplypipe 310 a. In addition, even if the inside of the reaction tube 203 isexposed to the atmospheric pressure in a substrate transfer step afterthe film-forming sequence described later is completed, the inside ofthe gas supply pipe 310 can be purged cyclically individually.Therefore, it is possible to further improve the degree of cleanlinessinside the gas supply pipe 310.

When a space around the manifold 226 is small due to the apparatusconfiguration, it is difficult to install the blocking part 101 and theexhaust part 102 in the space. However, by providing the boundary partand the furnace opening part 226 integrally, it is possible to installthe blocking part 101 and the exhaust part 102 in a space-saving mannerand to improve the maintainability of the apparatus.

Hereinafter, with reference mainly to FIGS. 7 through 10, the shut offvalve 101 provided close to and outside of the furnace opening part 226will be described in detail.

The configuration between the furnace opening part 226 and the blockingpart 101 in the embodiments may be a configuration as shown in FIG. 7 inwhich the furnace opening part 226 and the shut off valve 101 aredirectly connected (that is, the configuration where the piping isrecognizable from outside), or may be a configuration as shown in FIG. 8in which the furnace opening part 226 and the shut off valve 101 areintegrated (that is, the configuration where the piping is notrecognizable from outside). In addition, in FIGS. 7 and 8, the furnaceopening part 226 with the blocking part 101 are illustrated.

Although not shown, the exhaust part 102 may be integrally formed as aunited body with the furnace opening part 226 while being adjacent tothe blocking part 101. In addition, as shown in FIG. 9, the blockingpart 101 may be attached to the cooling mechanism.

The length (pipe length) of the piping installed between the furnaceopening part 226 and the switching part in FIG. 4 will be compared withthe length (pipe length) of the piping installed between the furnaceopening part 226 and the blocking part 101 according to the embodiments.Assuming that the pipe length of the embodiments shown in FIG. 7 is 100mm, the length ratio of the pipe length is about ⅕ to 1/30, and the pipelength including a connection part (not shown) of the embodiments shownin FIG. 8 is about 50 mm, the length ratio of its pipe length would beabout 1/10 to 1/60. The ideal pipe length is zero (that is, when nopiping is provided).

FIG. 10 illustrates a configuration in which the blocking part 101 isintegrated with the furnace opening part 226 in FIG. 8, that is, theblocking part 101 is attached on the side wall of the furnace openingpart 226 without providing any piping therebetween. While the blockingpart 101 is not illustrated in FIG. 10, a plurality of the blocking part101 is provided at the furnace opening part 226.

An end of the blocking part 101 is connected to the nozzle (or thenozzle support part 350) provided in the furnace opening part 226, andthe other end of the blocking part 101 is connected to the piping (thegas supply pipe 310 according to the embodiments) outside the furnaceopening part 226. FIG. 10 illustrates the blocking part 101 when it isopen. Referring to FIG. 10, a flow path of the gas extends from the gassupply pipe 310 to the nozzle part 340 via the blocking part 101.

In order to minimize the influence of the back diffusion of the processgas to the gas supply pipe 310, it is desirable not to provide thepiping between the nozzle support part 350 and the blocking part 101.However, it is impossible in terms of the configuration of the blockingpart 101. Thus, it is preferable that the blocking part 101 and thefurnace opening part 226 are integrally structured as shown in FIG. 10.

As shown in FIG. 3, the controller 280 serving as a control device(control mechanism) is constituted by a computer including a CPU(Central Processing Unit) 121 a, a RAM (Random Access Memory) 121 b, amemory device 121 c and an I/O port 121 d. The RAM 121 b, the memorydevice 121 c and the I/O port 121 d may exchange data with the CPU 121 athrough an internal bus 121 e. For example, an input/output device 122such as a touch panel is connected to the controller 280.

The memory device 121 c is configured by components such as a flashmemory and HDD (Hard Disk Drive). A control program for controlling theoperation of the substrate processing apparatus or a process recipecontaining information on the sequences and conditions of a substrateprocessing described later is readably stored in the memory device 121c. The process recipe is obtained by combining steps of the substrateprocessing described later such that the controller 280 can execute thesteps to acquire a predetermine result, and functions as a program.Hereinafter, the process recipe and the control program are collectivelyreferred to as a “program”. In the present specification, “program” mayindicate only the recipe, indicate only the control program, or indicateboth of them. The RAM 121 b is a work area where a program or data readby the CPU 121 a is temporarily stored.

The I/O port 121 d is connected to the above-described components suchas the MFCs 320 a through 320 f, the valves 330 a through 330 f, theshut off valves 101 a through 101 c, the exhaust part (exhaust valve)102 a through 102 c, the pressure sensor 245, the APC valve 244, thevacuum pump 246, the heater 207, the temperature sensor (thermocouple)1, the boat rotating mechanism 267 and the boat elevator 115.

The CPU 121 a is configured to read a control program from the memorydevice 121 c and execute the read control program. Furthermore, the CPU121 a is configured to read a recipe from the memory device 121 caccording to an operation command inputted from the input/output device122. According to the contents of the read recipe, the CPU 121 a may beconfigured to control various operations such as flow rate adjustingoperations for various gases by the MFCs 320 a through 320 f,opening/closing operations of the valves 330 a through 330 f,opening/closing operations of the shut off valves 101 a through 101 c,an opening/closing operation of the APC valve 244, a pressure adjustingoperation by the APC valve 244 based on the pressure sensor 245, a startand stop of the vacuum pump 246, a temperature adjusting operation ofthe heater 207 based on the temperature sensor 1, an operation ofadjusting rotation and rotation speed of the boat 217 by the boatrotating mechanism 267 and an elevating and lowering operation of theboat 217 by the boat elevator 115.

The controller 280 may be embodied by installing the above-describedprogram stored in an external memory device 123 into a computer. Forexample, the external memory device 123 may include a magnetic tape, amagnetic disk such as a flexible disk and a hard disk, an optical disksuch as a CD and a DVD, a magneto-optical disk such as MO, asemiconductor memory such as a USB memory and a memory card. The memorydevice 121 c or the external memory device 123 may be embodied by anon-transitory computer readable recording medium. Hereafter, the memorydevice 121 c and the external memory device 123 are collectivelyreferred to as recording media. In the present specification, the term“recording media” may indicate only the memory device 121 c, indicateonly the external memory device 123, and indicate both of the memorydevice 121 c and the external memory device 123. Instead of the externalmemory device 123, a communication means such as the Internet and adedicated line may be used for providing the program to the computer.

Hereinafter, the operation of the substrate processing apparatusaccording to the embodiments will be described. The substrate processingapparatus is controlled by the controller 280.

After the boat 217 charged with the wafers 200 are loaded into thereaction tube 203, the seal cap 219 airtightly seals the reaction tube203. By supplying the process gas into the reaction tube 203 while thewafers 200 are heated and maintained at a predetermined temperature inthe airtightly sealed reaction tube 203, the wafers 200 are subject to asubstrate processing such as a film-forming process.

By performing the film-forming process (substrate processing), forexample, by performing a film-forming sequence shown in FIG. 11, asilicon nitride film (SiN film) is formed on the wafers 200. That is,the SiN film is formed on the wafers 200 by performing a cycle of thefilm-forming sequence a predetermined number of times (once or more).The cycle may include a step of supplying HCDS gas onto the wafers 200in the process chamber 201, a step of removing the HCDS gas (residualgas) from the process chamber 201, a step of supplying NH₃ gas onto thewafers 200 in the process chamber 201 and a step of removing the NH₃ gas(residual gas) from the process chamber 201. The steps in the cycle areperformed non-simultaneously.

In the present specification, “substrate” and “wafer” may be used assubstantially the same meaning.

<Wafer Charging and Boat Loading Step>

After the boat 217 is charged with the wafers 200 (wafer charging), theboat 217 is elevated by the boat elevator 115 and loaded into theprocess chamber 201 (boat loading). With the boat 217 loaded, the sealcap 219 seals the lower end opening of the reaction tube 203 via theO-ring.

<Pressure and Temperature Adjusting Step>

The vacuum pump 246 vacuum-exhausts the process chamber 201 until theinner pressure of the process chamber 201 where the wafers 200 areaccommodated reaches a desired pressure (vacuum degree). In the pressureand temperature adjusting step, the inner pressure of the processchamber 201 is measured by the pressure sensor 245, and the APC valve244 is feedback-controlled based on the measured pressure. The vacuumpump 246 continuously vacuum-exhausts the process chamber 201 until atleast the processing of the wafers 200 is completed.

The heater 207 heats the process chamber 201 until the temperature ofthe wafers 200 in the process chamber 201 reaches a desired temperature.The amount of the current flowing to the heater 207 isfeedback-controlled based on the temperature detected by the temperaturesensor 1 such that the inner temperature of the process chamber 201 hasa desired temperature distribution. The heater 207 continuously heatsthe process chamber 201 until at least the processing of the wafers 200is completed.

The boat rotating mechanism 267 starts to rotate the boat 217 and thewafers 200. As the boat rotating mechanism 267 rotates the boat 217, thewafers 200 supported by the boat 217 are rotated. Until at least theprocess for the wafers 200 is completed, the boat rotating mechanism 267continuously rotates the boat 217 and the wafers 200.

<Film-Forming Process>

Next, after the temperature of the process chamber 201 is stabilized ata predetermined processing temperature, the film-forming process isperformed by performing a first step and a second step sequentially.

<First Step>

In the first step, the source gas (HCDS gas) is supplied onto the wafers200 in the process chamber 201. The first step includes at least apre-purge step, a source gas supply step, a source gas exhaust step anda post-purge step. The respective steps will be described below.

<Pre-Purge Step>

First, the valves 330 b and 330 e are opened to supply HCDS gas into thegas supply pipe 310 b. However, in the pre-purge step, the shut offvalve 101 b is closed. Thus, the HCDS gas is not supplied into theprocess chamber 201. Simultaneously, the valves 330 d and 330 f areopened to supply N₂ gas into the gas supply pipes 310 a and 310 c.Further, the shut off valves 101 a and 101 c may be opened such that N₂gas whose flow rate is adjusted by MFCs is supplied into the processchamber 201 at a predetermined flow rate, and the N₂ gas is exhaustedthrough the exhaust pipe 232. In the embodiments, preferably, theexhaust valve 102 b is provided adjacent to the shut off valve 101 b. Byopening the exhaust valve 102 b, the HCDS gas can be exhausted from thegas supply pipe 310 b to the exhaust pipe 232 through the exhaust valve102 b.

<Source Gas Supply Step>

Next, with the valves 330 b and 330 e open, the shut off valve 101 b isopened to supply the HCDS gas into the process chamber 201. In thesource gas supply step, the flow rate of the HCDS gas is adjusted by theMFC. After the flow rate of the HCDS gas is adjusted by the MFC, theHCDS gas is supplied onto the wafers 200 through the nozzle part 340 b,and exhausted through the exhaust pipe 232. In the source gas supplystep, the shut off valve 101 a and the shut off valve 101 c are closed.Thereby, it is possible to suppress the back diffusion of the HCDS gasto the gas supply pipes 310 a and 310 c.

<Source Gas Exhaust Step>

Next, with the shut off valve 101 a and the shut off valve 101 c closed,the shut off valve 101 b is closed. In the source gas exhaust step, withthe APC valve 244 open, the vacuum pump 246 vacuum-exhausts the insideof the process chamber 201 to remove a residual HCDS gas which did notreact or which contributed to the formation of a silicon (Si)-containinglayer serving as a first layer from the process chamber 201.

Then, the source gas supply step and the source gas exhaust step aresequentially performed (for example, three times in the embodiments).Thereby, the first layer is formed on the top surface of the wafers 200.Preferably, the first layer is formed on the top surface of the wafers200 by performing a cycle including the source gas supply step and thesource gas exhaust step a plurality of times. In the embodiments, thenozzle for supplying the HCDS gas into the process chamber 201 mayinclude a short pipe nozzle whose front end is open. In order to makethe gas concentration distribution uniform, the gas such as the sourcegas is supplied cyclically (which leads to a cyclic gas flow), asdescribed above. However, the method of supplying the gas isappropriately selected in accordance with the shape of the nozzle.

<Post-Purge Step>

After the first layer is formed, the valve 330 b is closed to stop thesupply of the HCDS gas. In the post-purge step, by opening the valves330 d through 330 f and the shut off valve 101 a through 101 c, the N₂gas is supplied into the process chamber 201. The N₂ gas serves as apurge gas, thus, it is possible to improve an effect of removing theresidual gas in the process chamber 201 from the process chamber 201.

<Gas Purging Step>

After the post-purge step is completed, by maintaining the valves 330 dthrough 330 f and the shut off valve 101 a through 101 c open, the N₂gas is continuously supplied into the process chamber 201. The flow rateof the N₂ gas is changed with a predetermined period. For example, theflow rate of the N₂ gas is switched between a first flow rate (flow rateA) and a second flow rate (flow rate B less than the flow rate A) apredetermined number of times. According to the embodiments, forexample, the switching of the flow rate of the N₂ gas is performedtwice.

In the embodiments, the first step includes the gas purging step forreliably exhausting the gas remaining in the process chamber 201 fromthe inside of the process chamber 201 before the reactive gas issupplied. However, the second step may also include the gas purgingstep. The gas purging step of the second step will be described later.

<Second Step>

After the first step is completed, NH₃ gas serving as the reactive gasis supplied onto the wafers 200 in the process chamber 38, i.e. onto thefirst layer formed on the wafers 200 in the process chamber 201. The NH₃gas is thermally activated and then supplied onto the wafers 200.

In the second step, the valves 330 a, 330 d and 101 a are controlled inthe same manners as in the first step. The flow rate of the NH₃ gas isadjusted by the MFCs, and the NH₃ gas with the flow rate thereofadjusted is supplied into the process chamber 201 through the nozzlepart 340 a and is then exhausted through the exhaust pipe 232. Thereby,the NH₃ gas is supplied onto the wafers 200. The NH₃ gas supplied ontothe wafers 200 reacts with the first layer, i.e. at least a portion ofthe silicon-containing layer formed on the wafers 200 in the first step.As a result, the first layer is thermally nitrided under non-plasmaatmosphere and modified into a second layer containing silicon (Si) andnitrogen (N), that is, a silicon nitride layer (SiN layer). Alternately,the NH₃ gas may be plasma-excited and then supplied onto the wafers 200to nitride the first layer under plasma atmosphere into the second layer(SiN layer).

After the second layer is formed, the valves 330 a and 330 d are closedto stop the supply of the NH₃ gas into the process chamber 201. Anunreacted gas, the NH₃ gas that has contributed to formation of thesecond layer and the reaction by-products remaining in the processchamber 201 are exhausted from the process chamber 201 in the samemanner as in the first step.

<Gas Purging Step>

The second step may further include the gas purging step to morereliably exhaust the gas remaining in the process chamber 201 from theprocess chamber 201 after the reactive gas is supplied.

Similar to the gas purging step of the first step, by opening the valves330 d through 330 f and the shut off valve 101 a through 101 c, the N₂gas is continuously supplied into the process chamber 201. The flow rateof the N₂ gas is changed with a predetermined period. For example, theflow rate of the N₂ gas is switched between the first flow rate (flowrate A) and the second flow rate (flow rate B less than the flow rate A)a predetermined number of times. According to the embodiments, forexample, the switching of the flow rate of the N₂ gas is performed fourtimes.

<Post-Purge Step>

After the gas purging step of the second step is performed apredetermined number of times, by maintaining the valves 330 d through330 f and the shut off valve 101 a through 101 c open, the N₂ gas whoseflow rate is adjusted to a predetermined flow rate is supplied into theprocess chamber 201 for a predetermined time to complete the purge step.Thereby, the film-forming sequence of the embodiments is completed.

<Performing Predetermined Number of Times>

By performing the cycle wherein the first step and the second stepaccording to the film-forming sequence shown in FIG. 11 are performednon-simultaneously in order a predetermined number of times (n times),the SiN film having a predetermined composition and a predeterminedthickness is formed on the wafers 200. It is preferable that the cycleis performed a plurality of times. That is, the cycle is performed(repeated) until the second film (SiN film) having the predeterminedthickness is obtained by controlling the second layer (SiN layer) formedin each cycle to be thinner than the second film (SiN film) having thepredetermined thickness and stacking the second layer (SiN) layer byperforming the cycle.

<Purging and Returning to Atmospheric Pressure Step>

After the film-forming process is completed, the valves 310 e and 310 fare opened to supply the N₂ gas into the process chamber 201 througheach of the gas supply pipes 310 b and 310 c, and then the N₂ gassupplied into the process chamber 201 is exhausted through the exhaustpipe 232. The gas or the reaction by-products remaining in the processchamber 201 are removed from the process chamber 201 by supplying the N₂gas (purging). Thereafter, the inner atmosphere of the process chamber201 is replaced with the inert gas (substitution by inert gas), and theinner pressure of the process chamber 201 is returned to atmosphericpressure (returning to atmospheric pressure).

<Boat Unloading and Wafer Discharging Step>

Thereafter, the seal cap 219 is lowered by the boat elevator 115 and thelower end of the reaction tube 203 is opened. The boat 217 with theprocessed wafers 200 charged therein is unloaded from the reaction tube203 through the lower end of the reaction tube 203 (boat unloading). Theprocessed wafers 200 are then unloaded (discharged) from the boat 217(wafer discharging).

According to the embodiments, the HCDS gas is supplied into the reactiontube 203 while opening/closing the shut off valve 101 provided at theboundary between the nozzle and the gas supply system. Thus, by closingthe shut off valve 101 connected to a process gas supply system otherthan the process gas supply system for supplying the HCDS gas, the HCDSgas is prevented from being diffused thereto. Therefore, it is possibleto reduce particles originated from the by-products in the piping suchas the gas supply pipe 310.

According to the embodiments, it is possible to suppress the backdiffusion of HCDS gas by closing the shut off valve 101 of theprocessing gas supply system other than the HCDS gas. Therefore, it ispossible to remarkably reduce the range that should be heated in thepiping constituting the process gas supply system for supplying the HCDSgas.

According to the embodiments, the processing gas supply system otherthan the processing gas supply system for supplying the HCDS gas alsoheats the piping where the HCDS gas is diffused. However, depending onthe kind of gas, it may be unnecessary to heat the piping. In addition,even if the gas makes it necessary to heat the piping, the heatingtemperature can be moderated. Therefore, it is possible to reduce therange where the piping should be heated to a high temperature forpreventing liquefaction of the HCDS, thereby leading to a reduction inthe heater cost.

FIG. 12 schematically illustrates the dependence of the flow rate of theN₂ gas with the change of the flow rate of the counter N₂ gas when thecounter N₂ gas is supplied through the two process gas supply mechanismsof the process gas supply system including the three mechanisms otherthan the process gas supply mechanism of the process gas supply systemfor supplying a film-forming gas (one of the source and the reactivegas). For example, when the film-forming gas is supplied through thefirst process gas supply mechanism, the counter N₂ gas is suppliedthrough the second process gas supply mechanisms and the third processgas supply mechanism.

For example, the processing conditions for obtaining the dependence areas follows:

The temperature of the wafers 200: 100° C. to 800° C., preferably, 400°C. to 750° C. For example, 630° C. according to the embodiments;

The inner pressure of the process chamber: 5 Pa to 4,000 Pa, preferably,10 Pa to 1,332 Pa;

The flow rate of the HCDS gas: 1 sccm to 2,000 sccm, preferably 50 sccmto 500 sccm;

The flow rate of the NH₃ gas: 100 sccm to 30,000 sccm;

The flow rate of the N₂ gas: 1 sccm to 50,000 sccm; and

The thickness of the SiN film: 0.2 nm to 100 nm.

FIG. 12 illustrates the average thicknesses and the uniformities offilms formed on the wafers 200 with respect to the presence and the flowrate of the counter N₂ gas. Specifically, the average thickness and theuniformity of a film formed on a surface of a wafer placed at anuppermost portion (indicated by “TOP” in FIG. 12) of a substrateprocessing region, the average thickness and the uniformity of a filmformed on a surface of a wafer placed at a center portion (indicated by“CNT” in FIG. 12) of the substrate processing region and the averagethickness and the uniformity of a film formed on a surface of a waferplaced at a lowermost portion (indicated by “BTM” in FIG. 12) of thesubstrate processing region are illustrated, respectively. In addition,the uniformities of the films between the wafers 200 in the above casesare also illustrated in FIG. 12. Hereinafter, the uniformity of the filmformed on the surface of the wafer is also referred to as “theuniformity in the wafer”, and the uniformity of the films between thewafers 200 is also referred to as “the uniformity between the wafers”.

In FIG. 12, “W/O COUNTER N₂ GAS” corresponds to the embodiments. Thatis, according to the embodiments, the shut off valve 101 provided in thegas supply system (that has supplied the counter N₂ gas into the processchamber 201 so far) is closed while the HCDS gas or the NH₃ gas issupplied. Therefore, it is possible to prevent the back diffusion of theHCDS gas or the NH₃ gas to the gas supply pipe 310, so that the supplyof the counter N₂ gas is not necessary.

When the counter N₂ gas is not supplied, the HCDS gas or the NH₃ gas isnot diluted by the counter N₂ gas. Thus, the concentration of the HCDSgas or the NH₃ gas in the process chamber 201 is higher than that of theHCDS gas or the NH₃ gas in case where the counter N₂ gas is suppliedaccording to the flow rates illustrated in FIG. 12. Therefore, theaverage thickness of the film formed on the wafers placed at each of theupper region (“TOP”), the center region (“CNT”) and the lower region(“BTM”) of the substrate processing region is higher than the case wherethe counter N₂ gas is supplied.

When the counter N₂ gas is not supplied, the HCDS gas or the NH₃ gas inthe process chamber 201 can contact the surface of each wafer 200uniformly (or in its entirety) without being affected by the counter N₂gas. Therefore, the uniformity in the wafer at each of the upper region(“TOP”), the center region (“CNT”) and the lower region (“BTM”) of thesubstrate processing region is lower than the case where the counter N₂gas is supplied.

In FIG. 12, as described above, “TOP” indicates that the wafer isdisposed at the uppermost portion of the substrate processing region,“BTM” indicates that the wafer is disposed at the lowermost portion ofthe substrate processing region and “CNT” indicates that the wafer isdisposed at the center portion of the substrate processing region. Forexample, if the wafers 200 are place at a substrate processing region ofa batch process furnace having 33 slots in total (i.e., in slot #1through slot #33), and dummy wafers are disposed at the slots #1 to #4and the slots #30 to #33, the substrate processing region would bedefined by the slots #5 to #29. In this case, “TOP” would indicate thatthe wafer is disposed at the slot #29, “CNT” would indicate that thewafer is disposed at the slot #17, and “BTM” would indicate that thewafer is disposed at the slot #5.

The uniformity in the wafer is obtained by measuring the thickness ofthe film at predetermined positions in the surface of the wafer andaveraging the measured thickness. The uniformity between the wafers iscalculated by: (i) obtaining the uniformities in the wafer for all ofthe wafers 200 placed in slots from “BTM” to “TOP” in the substrateprocessing region and (ii) averaging the obtained uniformities.According to the batch process furnace described above, the uniformitybetween the wafers is calculated by averaging the uniformities in thewafer obtained from 25 slots (that is, the slots #5 to #29).

According to the embodiments, by eliminating the need for the counter N₂gas, it is possible to improve the uniformity in the wafer and theuniformity between the wafers. Particularly, the uniformity between thewafers is significantly improved.

Next, referring to FIG. 13, a current film-forming sequence without theshut off valve and the film-forming sequence with the shut off valveaccording to the embodiments will be compared. Referring to FIG. 13, thetime required for replacing the gas in the reaction tube in the purgestep (also referred to as a “gas replacement step”) after the processgas is supplied is remarkably improved.

As shown in FIG. 4, the piping extends to the opening/closing valveclosest to the furnace opening part 226. In a conventional purge step,the entire range of the piping extending to this opening/closing valveshould be exhausted by the vacuum pump 246. Therefore, the exhaustefficiency is low, and time is spent to perform the gas replacementstep. However, according to the embodiments, it is sufficient tovacuum-exhaust only a partial range of the piping extending to thenozzle part 340 because the vacuum pump 246 operates while the blockingpart 101 is closed. Thus, the exhaust efficiency according to theembodiments can be remarkably improved as compared with the conventionalsequence. In particular, as shown in FIG. 13, it is possible to shortenthe time required for the cycle purge step after the process gas issupplied.

For example, referring to FIG. 13, the time required to perform onecycle of the current film-forming sequence is 51 seconds, and the timerequired to perform one cycle of the film-forming sequence according tothe embodiments with the shut off valve 101 is 41 seconds. Thus,according to the embodiments, the time required to perform one cycle canbe shortened by about 20% (10 seconds) compared with that of the currentfilm-forming sequence.

Thus, according to the embodiments, by closing the shut off valve in thepurge step after the process gas is supplied, it is possible toremarkably improve the gas replacement efficiency in the reaction tube.Therefore, it is possible to shorten the time required for the purgingstep of the film-forming sequence. In addition, it is possible toshorten the time of performing the film-forming sequence.

According to the embodiments, one or more advantageous effects describedbelow can be achieved.

(a) According to the embodiments, it is possible to suppress the backdiffusion of the gas to the upstream side of the gas supply pipe byproviding shut off valve outside of the manifold and integrating theshut off valve with the manifold.

(b) According to the embodiments, the shut off valve is provided in thevicinity of the side wall of the furnace opening part. Thus, it ispossible to suppress the back diffusion of the process gas into the gassupply pipe by closing the shut off valve while the process gas issupplied to the reaction tube through other gas supply pipe.

(c) According to the embodiments, by suppressing the back diffusion ofthe process gas to the upstream side of the gas supply pipe, theby-products such as ammonium chloride can be prevented from adhering tothe inside of the gas supply pipe. Therefore, it is possible to reducethe particles originated from the by-products.

(d) According to the embodiments, it is possible to suppress the backdiffusion of the process gas into the gas supply pipe. Thus, it becomesunnecessary to provide the inert gas (the counter N₂ gas in theembodiments) for suppressing the back diffusion of the film-forming gasto other gas supply pipes when the film-forming gas is supplied to thegas supply pipe. Therefore, it is possible to suppress the waste of theinert gas.

(e) According to the embodiments, it is possible to reduce the rangethat should be heated in the piping and to moderate the heatingtemperature for the piping by blocking the atmosphere of the processchamber from the atmosphere of each gas supply pipe.

(f) According to the embodiments, since the shut off valve is provided,it is possible to suppress the back diffusion of a vaporized gassupplied through one gas supply pipe into the other gas supply pipes.Therefore, although it depends on the gas supplied into the other gassupply pipes, it is possible to reduce the range that should be heatedin the piping if the other gas supply pipes themselves do not need to beheated.

(g) When the gas supply pipe itself needs to be heated, the temperatureof the heater must be set to that of the gas supply pipe even in casewhere the temperature uniformity requirement at a high temperature isnot so high. However, according to the embodiments, the temperatureuniformity at a high temperature of the heater need not be as high asthat of the gas supply pipe because the shut off valve is provided.Therefore, it is possible to use an inexpensive heater such as a heatercapable of heating at a relatively low temperature and a heater having asimple heat insulating structure.

(h) According to the embodiments, it is possible to improve theuniformity of film thickness as a result by closing the shut off valveinstead of supplying the counter N₂ gas.

(i) According to the embodiments, by closing the shut off valve andsuppressing the back diffusion of the gas to the upstream side of thegas supply pipe, it is possible to improve the gas replacementefficiency in the process chamber, and to shorten the time of performingthe film-forming sequence.

While the above-described embodiments are described by way of an examplein which the vertical type semiconductor manufacturing apparatus is usedto form the film, the above-described technique is not limited thereto.For example, the above-described technique may be applied to the filmformation using a horizontal type semiconductor manufacturing apparatus.

While the above-described embodiments are described by way of an examplein which the HCDS serving as the source gas is used to form the film,the above-described technique is not limited thereto. Instead of theHCDS gas, for example, an inorganic halosilane source gas such asmonochlorosilane (SiH₃Cl, abbreviated as MCS) gas, dichlorosilane(SiH₂Cl₂, abbreviated as DCS) gas, trichlorosilane (SiHCl₃, abbreviatedas TCS) gas, tetrachlorosilane gas, that is, silicon tetrachloride(SiCl₄, abbreviated as STC) gas and octachlorotrisilane (Si₃Cl₈,abbreviated as OCTS) gas may be used as the source gas. Instead of theHCDS gas, for example, an amino-based (amine-based) silane source gasfree of halogen such as trisdimethylaminosilane (Si[N(CH₃)₂]₃H,abbreviated as 3DMAS) gas, tetrakisdimethylaminosilane (Si[N(CH₃)₂]₄,abbreviated as 4DMAS) gas, bisdiethylaminosilane (Si[N(C₂H₅)₂]₂H₂,abbreviated as BDEAS) gas and bis(tertiary-butyl amino)silane gas(SiH₂[NH(C₄H₉)]₂, abbreviated as BTBAS) gas may also be used as thesource gas. Instead of the HCDS gas, for example, an inorganic silanesource gas free of halogen such as monosilane (SiH₄, abbreviated as MS)gas, disilane (Si₂H₆, abbreviated as DS) gas and trisilane (Si₃H₈,abbreviated as TS) gas may also be used as the source gas.

While the above-described embodiments are described by way of an examplein which the NH₃ serving as the reactive gas is used to form the film,the above-described technique is not limited thereto. Instead of the NH₃gas, for example, a hydrogen nitride-based gas such as diazene (N₂H₂)gas, hydrazine (N₂H₄) gas, N₃H₈ gas and compounds thereof may be used asthe reactive gas. Instead of the NH₃ gas, for example, anethylamine-based gas such as triethylamine ((C₂H₅)₃N, abbreviated asTEA) gas, diethylamine ((C₂H₅)₂NH, abbreviated as DEA) gas andmonoethylamine (C₂H₅NH₂, abbreviated as MEA) gas may also be used as thereactive gas. Instead of the NH₃ gas, for example, a methylamine-basedgas such as trimethylamine ((CH₃)₃N, abbreviated as TMA) gas,dimethylamine ((CH₃)₂NH, abbreviated as DMA) gas and monomethylamine(CH₃NH₂, abbreviated as MMA) may also be used as the reactive gas.Instead of the NH₃ gas, for example, an organic hydrazine-based gas suchas trimethylhydrazine ((CH₃)₂N₂(CH₃)H, abbreviated as TMH) gas may alsobe used as the reactive gas.

While the above-described embodiments are described by way of an examplein which the SiN film is formed by using the HCDS gas as the source gasand the nitrogen (N)-containing gas such as the NH₃ gas as the reactivegas, the above-described technique is not limited thereto. For example,the above-described techniques may be applied to the formations of afilm such as a silicon oxide film (SiO film), a silicon oxynitride film(SiON film), a silicon oxycarbonitride film (SiOCN film), a siliconoxycarbide film (SiOC film), a silicon carbonitride film (SiCN film), asilicon boronitride film (SiBN film) and a silicon boron carbonitridefilm (SiBCN film) according to the film-forming sequence described aboveby using an oxygen-containing gas such as an oxygen (O₂) gas, acarbon-containing gas such as a propylene (C₃H₆) gas and aboron-containing gas such as boron trichloride (BCl₃) instead of or inaddition to the gases described above.

In addition, the order of supplying the gases may be changedappropriately. When the above-described technique is applied to thefilm-forming process of the above-described films, the processingconditions of film-forming process for the above-described films may besubstantially the same as those of the film-forming process according tothe embodiments and the same advantageous effects as the embodiments maybe obtained. That is, the above-described technique may be preferablyapplied to form a film containing a predetermined element such as asemiconductor element and a metal element.

While the above-described embodiments are described by way of an examplein which the film is deposited on the substrate, the above-describedtechnique is not limited thereto. For example, the above-describedtechnique may be preferably applied to the processes such as anoxidation process, a diffusion process, an annealing process and anetching process of the substrate or the film or layer formed on thesubstrate. The above-described embodiments and modified examples may beappropriately combined. The processing conditions of the combinationsmay be substantially the same as the above-described embodiments or themodified examples.

While the technique is described by way of the above-describedembodiments and the examples, the above-described technique is notlimited thereto. The above-described technique may be modified invarious ways without departing from the gist thereof.

The above-described technique can be preferably applied to a substrateprocessing apparatus for forming a film on a substrate.

According to the technique described herein, it is possible to providean opening/closing valve in the vicinity of a furnace opening part.

What is claimed is:
 1. A substrate processing apparatus comprising: aprocess chamber defined at least by a reaction tube and a furnaceopening part provided at a lower portion of the reaction tube; a nozzleprovided at the furnace opening part and extending from the furnaceopening part to an inside of the reaction tube; a gas supply systemprovided at an upstream side of the nozzle; a blocking part provided ata boundary between the gas supply system and the nozzle; and acontroller configured to control the gas supply system and the blockingpart such that the blocking part co-operates with the gas supply systemto supply gases into the process chamber through the nozzle.
 2. Thesubstrate processing apparatus of claim 1, wherein the blocking part isinstalled close to a side wall of the furnace opening part withoutproviding a pipe between the blocking part and the side wall of thefurnace opening part.
 3. The substrate processing apparatus of claim 1,further comprising: a switching part provided at an upstream side of theblocking part; and an exhaust part configured to exhaust an inside of apipe provided between the switching part and the blocking part.
 4. Thesubstrate processing apparatus of claim 1, further comprising: a coolingpart configured to cool the blocking part by supplying a coolant to theblocking part.
 5. The substrate processing apparatus of claim 1, furthercomprising: a furnace opening box part capable of performing localexhaust of the furnace opening part, wherein the blocking part isprovided in the furnace opening box part.
 6. A substrate processingapparatus comprising: a first nozzle and a second nozzle provided at afurnace opening part and extending from the furnace opening part to aninside of a reaction tube; a first gas supply system provided at anupstream side of the first nozzle; a second gas supply system providedat an upstream side of the second nozzle; a first blocking part providedat a boundary between the first gas supply system and the first nozzle;a second blocking part provided at a boundary between the second gassupply system and the second nozzle; a controller configured to controlthe first gas supply system, the first blocking part, the second gassupply system and the second blocking part such that the first gassupply system co-operates with the first blocking part to supply a firstgas into the reaction tube and the second gas supply system co-operateswith the second blocking part to supply a second gas into the reactiontube.
 7. The substrate processing apparatus of claim 6, wherein thecontroller is further configured to control the first gas supply system,the first blocking part, the second gas supply system and the secondblocking part to perform at least one of: supplying the first gas to asubstrate in the reaction tube by opening the first blocking partwithout supplying the second gas by closing the second blocking part;and supplying the second gas to the substrate in the reaction tube byopening the second blocking part without supplying the first gas byclosing the first blocking part.
 8. The substrate processing apparatusof claim 6, further comprising: an exhaust system configured to exhausta gas from the reaction tube, wherein the controller is furtherconfigured to control the first blocking part, the second blocking partand the exhaust system to exhaust the first gas or the second gas fromthe reaction tube by closing the first blocking part and the secondblocking part when a supply of the first gas or the second gas to thesubstrate in the reaction tube is terminated.
 9. The substrateprocessing apparatus of claim 6, further comprising: an exhaust systemconfigured to exhaust a gas from the reaction tube, wherein thecontroller is further configured to control the first gas supply system,the first blocking part, the second gas supply system, the secondblocking part and the exhaust system to cyclically purge the inside ofthe reaction tube.
 10. The substrate processing apparatus of claim 6,wherein the controller is further configured to control the first gassupply system, the first blocking part, the second gas supply system andthe second blocking part such that the first blocking part co-operateswith the first gas supply system and the second blocking partco-operates with the second gas supply system to supply an inert gasinto the reaction tube.
 11. The substrate processing apparatus of claim1, wherein the blocking part connected to a nozzle extending from aninner wall of the furnace opening part to an inside of the reaction tubeis provided at the furnace opening part without providing a pipe betweenthe blocking part and an outer wall of the furnace opening part.
 12. Amethod of manufacturing a semiconductor device, comprising: (a) loadinga substrate retainer accommodating a plurality of wafers into a reactiontube; and (b) processing the plurality of wafers by supplying a firstgas through a first nozzle into the reaction tube by controlling a firstgas supply system to co-operate with a first blocking part and supplyinga second gas through a second nozzle into the reaction tube bycontrolling a second gas supply system to co-operate with a secondblocking part, wherein the first nozzle and the second nozzle extendfrom an inner wall of a furnace opening part to an inside of thereaction tube, the first blocking part and the second blocking part areconnected to the first nozzle and the second nozzle, respectively, andthe first gas supply system and the second gas supply system areprovided at upstream sides of the first nozzle and the second nozzle,respectively.